Democrats won control of at least seven state capitols, including upsetting Wisconsin Governor Scott Walker and turning a key state on the 2020 presidential map blue. Republicans, however, held Ohio, Florida, and Arizona, other key states in 2020.

A night of historic diversity wins saw Congress gain its youngest-ever woman, and its first-ever Muslim women and Native American women. Colorado elected the US's first openly gay governor.

Historically, presidents tend to experience a midterm correction that sees the opposition party winnow away their grip on power in the legislature. These results fall generally in line with that trend.

But voters did send a clear message with both the volume and character of their ballots.

What voters care about

In Trump's midterm campaign push, he repeatedly hammered the issue of immigration, often blaming Democrats for a caravan of Central American migrants heading towards the US's southern border, whom he branded "invaders."

Democrats, who have struggled to get a word in around Trump's media dominance, explicitly tried to focus the voting public on healthcare, and look to have narrowly won the messaging battle.

An Associated Press exit poll of more than 115,000 voters found that 26% named healthcare as the most important issue facing the country. Immigration trailed just behind at 23%. These numbers roughly track with Google search data that showed more of the voting public searching for healthcare than immigration.

Among Democrat voters, nearly 40% named healthcare as their priority, with a similar number of Republicans picking immigration.

Democrats specifically hammered Republicans on the issue of healthcare protections for people with preexisting medical conditions, which the GOP has consistently worked to erode. Trump may have entered damage control mode by suggesting throughout the campaign that his party would protect those with preexisting conditions, even though historically he has worked for the opposite.

As results started rolling in, a triumphant Nancy Pelosi, now soon to be the House Majority Leader, declared that the elections were "about stopping the GOP and [Senate Majority Leader] Mitch McConnell's assault on Medicare, Medicaid, affordable health care, and millions of Americans living with pre-existing medical conditions."

Trump's tax cuts a political flop

Another key Trump talking point, the soaring US economy, came in with 19%, and other polling indicated Trump's key contribution to government financial policy, the Tax Cuts and Jobs Act, flopped.

Just 28% of people surveyed said the act had helped them, according to an exit poll conducted by CNN, NBC, ABC, and other major news outlets. Another 45% said it did nothing for them, and 28% said it hurt them.

An internal GOP poll obtained by Bloomberg showed that the party had admitted that Republicans lost the messaging battle over the tax changes.

2020 battleground

Democrats and Republicans understood Tuesday night to mean more than just winning seats in the legislature — it is also preparing the battleground for the 2020 presidential race.

A strong showing from Democrats winning governorships in key states like Wisconsin and Michigan will allow them to reshape congressional and state legislative districts. This redistricting may prove critical to the 2020 presidential maps.

But the fabled "blue wave" did not arrive with tsunami force. While some Democrats like Amy Klobuchar, who handily won re-election in Minnesota, may have come out of the races with 2020 buzz, the party still has no clear front-runner to take on Trump.

Overall, the elections saw a stunning acceptance of racial, gender, and sexual diversity with voters mainly focused on "kitchen table" issues, like healthcare, rather than identity issues like immigration.